Storm identification, tracking, and forecasting make up an essential part of weather radar and severe weather surveillance operations. Existing nowcasting algorithms using radar data can be generally classified into two categories: centroid and cross-correlation tracking. Thunderstorm Identification, Tracking, and Nowcasting (TITAN) is a widely used centroid-type nowcasting algorithm based on this paradigm. The TITAN algorithm can effectively identify, track, and forecast individual convective storm cells, but TITAN tends to provide incorrect identification, tracking, and forecasting in cases where there are dense cells whose shape changes rapidly or where clusters of storm cells occur frequently. Aiming to improve the performance of TITAN in such scenarios, an enhanced TITAN (ETITAN) algorithm is presented. The ETITAN algorithm provides enhancements to the original TITAN algorithm in three aspects. First, in order to handle the false merger problem when two storm cells are adjacent, and to isolate individual storm cells from a cluster of storms, ETITAN uses a multithreshold identification method based on mathematical morphology. Second, in the tracking phase, ETITAN proposes a dynamic constraint-based combinatorial optimization method to track storms. Finally, ETITAN uses the motion vector field calculated by the cross-correlation method to forecast the position of the individual isolated storm cells. Thus, ETITAN combines aspects of the two general classes of nowcasting algorithms, that is, cross-correlation and centroid-type methods, to improve nowcasting performance. Results of experiments presented in this paper show the performance improvements of the ETITAN algorithm.

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In this paper, we take a look at the state-of-the-art of the theory and applications of the so-called grey systems theory founded in the 1980s. After a brief historical review of the development history of this theory, we look at the main blocks of the theory followed by several successful applications. It is our hope that a reader who does not know anything about this branch of scientific exploration will gain a firm understanding of the basics so that the rest of this special issue becomes possible to comprehend.

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PurposeThis paper aims to show that systemic methods and thinking can be used to develop useful tools to address problems open in traditional science, such as Newtonian physics, universal gravitation, planetary motions, and the three‐body problem.Design/methodology/approachExpanded on the yoyo model introduced earlier for general systems, a new figurative analysis method is introduced in this paper.FindingsAfter establishing its theoretical and empirical foundations, this method is used to generalize Newton's laws of mechanics by addressing several unsettled problems in the history. Through the concept of equal quantitative effects, it is argued that this new method possesses some strength not found in pure quantitative methods. After studying the characteristics of whole evolutions of converging and diverging fluid motions, the concept of time is revisited using the new model. As further applications of the new method, one covers Kepler's laws of planetary motion, Newton's law of universal gravitation, and explains why planets travel along elliptical orbits, why no external forces are needed for systems to revolve about one another, and why binary star systems, tri‐nary star systems, and even n‐nary star systems can exist, for any natural number n≥2. By checking the study of the three‐body problem, a brand new method is provided to analyze the movement of three stars, visible or invisible. At the end, some open problems are cast for future research.Originality/valueThis paper shows for the first time in history that several well‐established laws in physics can be generalized using systemic thinking. Beyond that, an operative method of analysis is introduced to investigate problems that have been extremely difficult to handle in the scientific history. With adequate quantitative tools developed to accompany this method, it can be reasonably expected that an active systemic scientific era with a slightly different tilt from the contemporary science will follow shortly.